Automatic transmissions operating with several shiftable gear stages, and without a group-shifting procedure, are well known. DE 199 12 480 A1, for example, discloses an automatic transmission of this class having three individual planetary gearsets as well as three brake devices and two clutches for the shifting of six forward gears and one reverse direction gear. This disclosure provides a very satisfactory transmission ratio motor vehicles with a high overall spread of gear ratios and favorable gear stage accessibility to which can be added a high starting ratio in the forward direction. The individual gear stages are achieved by selective closing of respectively two of the six shifting elements so that for the switching from one gear position to the next successive higher or lower stage relative to the current activated shifting elements, respectively only one shifting element is opened and another shifting element is closed.
During this procedure, an input drive shaft of the automatic transmission is continually connected with a sun gear of the second planetary gearset. Further, the input drive shaft, by way of the first clutch, can be connected by a link to the first planetary gearset, and/or alternately, this connection can be made by the second clutch with a link of the first planetary gearset. Additionally, or as an alternate, the sun gear of the first planetary gearset can be made affixed to the housing of the automatic transmission by the first brake. This is also possible using the link of the first planetary gearset with the second brake. Yet a third method of making the connection to the transmission housing is to employ a sun gear of the third planetary gearset with the third brake.
For the kinematic coupling of the individual planetary gears with one another, DE 199 12 480 A1 teaches two different versions. In the first version, provision is made that an output drive of the automatic transmission is continually bound with a link of the third planetary gearset and an interior gear of the first planetary gearset. Moreover, a link of the first planetary gearset is continually in connection with an internal gear of the secondary planetary gearset and a link of the second planetary gearset is always in connection with an internal gear of the third planetary gearset. During this interconnected occurrence, the input drive shaft and the output drive shaft can be placed co-axially to one another on oppositely lying sides of the transmission housing or, just as well, be placed axis-parallel on the same side of the housing. In the second version, the provision is that the output drive shaft is continually bound with the link of the second planetary gearset and the interior gear of the first planetary gearset, while the link of the first planetary gearset is continually connected to the interior gear of the third planetary gearset and, finally that the internal gear of the second planetary gearset is continually in contact with the link of the third planetary gearset. A design of this kind is especially appropriate only for a co-axial arrangement of the input-output drive shafts.
Taking into consideration the spatial positioning of the planetary gearsets, the DE 199 12 480 A1 patent further proposes the co-axial placement of the three planetary gearsets in a row beside one another, whereby the second planetary gearset finds itself axially interposed between the first and the third planetary gearsets. In relation to the spatial arrangement of the individual shifting elements in regard to one another, and in regard to the planetary gearsets, the proposal of DE 199 12 480 A1 extends itself so that the first and second brakes are always positioned precisely next to one another, whereby the second brake borders itself always exactly directly on the first planetary gearset, and the third brake is always to be located on that side of the third planetary gearset which is remote from the third planetary gearset, while the two clutches are always directly located next to one another. In a first variation of positioning, both clutches are to be found upon that side of the first planetary gearset which is remote from the third planetary gearset, whereby the first clutch is placed immediately proximal to the first brake and nearer to the first planetary gearset than is the second clutch. In connection with a non-co-axial location of the input and output drives, in a second variation arrangement, the proposal of a second positioning variation is that both clutches are located on that side of the third planetary gearset, which is remote from the first planetary gearset, whereby the second clutch is placed nearer to the third planetary gearset than is the first clutch and axially borders an output spur gear, which is operationally connected with the output drive shaft which, once again, is placed on that side of the third brake, which is remote from the third planetary gearset.
The purpose of the present invention is to present alternative component positioning for the known automatic transmission arising from the state of the technology of DE 199 12 480 A1 to achieve a transmission construction of the most compact possible dimensioning. Advantageously the automatic transmission can find use in a motor vehicle non-co-axial transmission input drive shaft and transmission output drive shaft, with the comparatively, most simple modifications. Application can also be found in installation in a motor vehicle with a standard input drive and co-axial positioning of transmission input and transmission output drive shafts.